1. Field of the Invention
The present invention relates to chemical vapor deposition (CVD) apparatuses, vaporizers for CVD apparatuses, and semiconductor devices, and in particular to a CVD apparatus capable of long-term, reliable production of CVD film with good quality, a vaporizer for a CVD apparatus, and a semiconductor device manufactured thereby.
2. Description of the Background Art
In recent years, there has been a further advancement in the integration of devices such as semiconductor memory. For instance, there has been a rapid advancement in enhancing the integration of a dynamic random access memory, quadrupled in the number of bits in three years. Such integration aims at achieving rapid device operation, reducing device power consumption, reducing device cost, and the like. While semiconductor memory and the like are highly integrated as described above, a capacitor, a component of such devices, is required to store a certain quantity of electric charge. Thus, along with the advancement in the integration of devices, there have also been developed a technique for forming a material for a capacitor""s dielectric film into an extremely thin film, a technique for forming a capacitor of a complex, three-dimensional structure to increase the surface area of the capacitor, and other techniques.
Main traditional materials for dielectric film include silicon oxide (SiO2) film. Due to its physical properties, however, it is extremely difficult to further reduce currently used silicon oxide film in thickness, and it has been accordingly noted that silicon oxide film is replaced with a material having a higher dielectric constant that silicon oxide film, since using a material having a dielectric constant higher than conventional as a material for a capacitor""s dielectric film can increase the density of the electric charge stored in the capacitor. When a material of a high dielectric constant is used as a dielectric film to achieve a storage of electric charge comparable to that achieved by a conventional capacitor, the dielectric film may have a thickness greater than that formed of silicon oxide film. If a dielectric film may have a thickness increased to some extent, the process for forming the dielectric film can be improved in controllability and the dielectric film can thus be enhanced in reliability. That is, there are a multitude of advantages in using a material of a high dielectric constant as a dielectric film material.
Such capacitor""s dielectric film is also sought to have small current leakage as an important characteristic thereof. To achieve such small current leakage, in general the dielectric film preferably has an equivalent SiO2 film thickness of no more than 0.5 nm, and a leakage current density of no more than 2xc3x9710xe2x88x927 A/cm2 when a voltage of 1V is applied.
The density of electric charge stored in a capacitor and other properties also significantly depend on the material for the capacitor""s electrode, which is required to be highly stable and have good workability.
Furthermore it is also considered to use a material of a lower electrical resistance than conventional as a wiling material in a highly integrated semiconductor device as above to operate the device rapidly.
As such, oxide-type dielectrics including tantalum oxide (Ta2O5), lead zirconate titanate (PZT), lead lanthanum zirconate titanate (PLZT), strontium titanate (ST), barium titanate (BT), and barium strontium titanate ((Ba, Sr) TiO2 (hereafter referred to as BST)) are considered as possible materials for a capacitor""s dielectric film. Furthermore, platinum, ruthenium, iridium and a conductive oxide thereof or SrRuO3 are considered as possible materials for a capacitor""s electrode. Copper is also considered as an alternative wiring material to aluminum, a conventional wiring material.
Generally, in forming a thin film on a capacitor""s electrode of a micro-fabricated memory device having fine steps it is preferable to employ a film deposition method through a chemical vapor deposition (CVD) which allows complex geometry to be covered satisfactorily. The CVD is also most advantageous in simplifying the process. In this CVD, an organometallic compound containing a predetermined type of metal is used as a material for a thin film. Vaporizing the material and spraying the vaporized material onto a substrate allows formation of a thin film with a high dielectric constant or capacitor""s electrode. However, most materials conventionally used for forming a thin film with a high dielectric constant are disadvantageously not stable nor have good vaporization characteristics.
Under such circumstances, some of the Inventors have invented, as disclosed in Japanese Patent Laying-Open No. 7-268634, a CVD film material with a greatly enhanced vaporization characteristic by dissolving a solid material such as an organometallic compound in an organic solvent called tetrahydrofuran or THF (C4H8O) to provide a solution thereof. Some of the Inventors have also invented, as disclosed in Japanese Patent Laying-Open No. 8-186103, a CVD apparatus for use with a liquid material that is capable of vaporizing the above-mentioned solution of the material (a liquid material) and supplying it stably to the CVD apparatus""s reaction chamber. Furthermore, some of the Inventors have succeeded in using the CVD apparatus disclosed in Japanese Patent Laying-Open No. 8-186103 to form a thin film of a high dielectric constant having good surface morphology and electrical characteristics. Some of the Inventors have also invented, as disclosed in U.S. patent application Ser. No. 09/150,212, a CVD apparatus and CVD process condition allowing stable vaporization of a liquid material in a vaporization chamber.
It has been found, however, that it is difficult to use such CVD apparatus for use with a liquid material for a long term to reliably form thin films of a high dielectric constant with good characteristics. As the Inventors examined the apparatus, it has been found that the problem is caused by a solid component of an organometallic compound or the like that is separated from the liquid material in the CVD apparatus""s vaporization chamber. This will be described in detail below with reference to the drawings.
FIG. 8 schematically shows a vaporizer as a vaporizer for use with a CVD apparatus related to the present invention. The vaporizer will now be described with reference to FIG. 8.
Referring to FIG. 8, a vaporizer 121 as the vaporizer includes a body 121a of the vaporizer and an upper lid 121b of the vaporizer. A rod heater 122 is varied in body 121a and upper lid 121b. Upper lid 121b is provided with a vaporizer inlet 121c for supplying into vaporizer 121 a mixture of a liquid material and nitrogen gas as a carrier gas. Inlet 121c is connected to a material supply tube 126a via a connecting member 121d. Material supply tube 126a is connected via a connecting member to a material transport tube (not shown) connected to a container holding the liquid material. Body 121a is also provided with a vaporizer outlet 101b for exhausting a vaporized material. Outlet 101b is connected via a transport tube to a reaction chamber for forming a CVD film. Outlet 101b and the transport tube connected thereto are provided with a heater 124.
Herein the material transport tube is typically a narrow tube of stainless steel. Material supply tube 126a is a narrow tube, e.g., of polytetrafluoroethylene (PTFE), polyimide. Body 121a and upper lid 121b are formed of metal, preferably a highly heat-conductive metal, such as aluminum, copper. Inlet 121c and outlet 101b and connecting member 121d may be formed, e.g., of stainless steel.
In such vaporizer 121, from an end of material supply tube 126a that is located internal to vaporizer 121 a liquid material is scattered or sprayed together with a carrier gas and thus supplied into vaporizer 121. The liquid material introduced into vaporizer 121 collides against the internal wall of vaporizer 121. Since body 121a and upper lid 121b have been heated by rod heater 122, the liquid material colliding against the internal wall of vaporizer 121 can vaporize instantly. The vaporized liquid material (referred to as a xe2x80x9cgaseous materialxe2x80x9d hereinafter) is exhausted from outlet 101b and thus supplied to a reaction chamber of the CVD apparatus.
Herein, to form a BST film in the CVD apparatus, vaporizer 121 is supplied with liquid materials respectively prepared by dissolving solid Ba (DPM)2, Sr (DPM)2, TiO (DPM)2, in THF. It should be noted that DPM represents dipivaloylmethane of xcex2-diketon type.
Using such liquid materials as above in a CVD apparatus for use with liquid materials provided with such a vaporizer as shown in FIG. 8, has allowed a thin film to be formed of a material of a high dielectric constant such as the BST film. However, the Inventors have found that the CVD apparatus provided with the FIG. 8 vaporizer has a disadvantage, as described below, when it is used for a long period of time to provide a film-formation process using such a liquid material as above.
More specifically, referring to FIG. 8, vaporizer 121, heated by rod heater 122, transfers heat to material supply tube 126a connected to vaporizer 121 and thus also heats material supply tube 126a. As a result, the solvent of a liquid material such as THF can partially be vaporized in material supply tube 126a. When an organic solvent such as THF partially vaporizes, an organometallic compound as a solute dissolved in the liquid material can partially be separated as a solid in material supply tube 126a. Such separation of the organometallic compound serving as a CVD film material (referred to as a xe2x80x9cvaporization-attributable residuexe2x80x9d hereinafter) will accumulate internal to vaporizer 121 and material supply tube 126a. Such accumulated residue negatively affects vaporization characteristics of the liquid material. Thus the gaseous material cannot be sent reliably from the vaporizer to the reaction chamber, disadvantageously resulting in degraded properties of a produced CVD film.
Furthermore, the vaporization-attributable residue that is accumulated, e.g., in vaporizer 121 can also be exhausted from outlet 101b as a powdery, solid component together with the vaporized material and introduced into the reaction chamber. In such a case the residue can be taken as an impurity into a CVD film in the reaction chamber and thus degrade the quality of the CVD film. This has been a cause of unsatisfactory operation of memory devices and the like which employ such CVD film. Furthermore, since using the CVD apparatus as described above for a long period of time results in a vaporization-attributable residue accumulating in vaporizer 121 as an impurity, the CVD apparatus used for an increased period of time has an increased possibility of the problems as described above and can thus not provide long-term, reliable production of CVD film with good quality.
Furthermore, the vaporization of an organic solvent, such as THF, partially heated and vaporized in material supply tube 126a can vary the flow rate of that mixture of a liquid material and a carrier gas which is supplied to vaporizer 121 via material supply tube 126a. This will vary the supply rate of the liquid material supplied to vaporizer 121 and hence the rate at which the material vaporized in vaporizer 121 is supplied to the reaction chamber. Thus the reliability of the CVD film formation process is degraded, and if the material supply rate varies significantly a CVD film may have an uneven composition. As a result, semiconductor devices, such as memory devices, using such CVD film have problems including unsatisfactory operation.
Furthermore, while material supply tube 126 is formed, e.g., of PTFE, as described above, such material is less heat-resistive than typical metal materials. Thus, when material supply tube 126a receives the heat from vaporizer 121, material supply tube 126a can be deformed, degraded in its properties and the like, and thus must be replaced frequently. Thus the process for CVD film formation cannot be provided continuously for a long period of time, resulting in reduced production efficiency of semiconductor devices such as memory devices. This prolongs the process for manufacturing semiconductor devices and thus disadvantageously increases the cost for manufacturing the same.
Furthermore, a vaporization-attributable residue accumulating in vaporizer 121 adheres directly to the metal members configuring body 121a and upper lid 121b of the vaporizer 121. Accordingly, body 121a and upper lid 121b must be cleaned to remove the residue therefrom. Such cleaning operation is a significant disadvantage in efficiently operating the CVD apparatus, since it is a cumbersome operation, requiring a long time. Such existence of a vaporization-attributable residue that prevents effective operation of the CVD apparatus results in increasing the cost for manufacturing semiconductor devices.
U.S. Pat. No. 5,204,314 discloses another vaporizer for a CVD apparatus proposed by Kirlin et al, Advanced Technology Materials, Inc., U.S. This proposed vaporizer, however, also has a similar problem, suffering from a solid matter produced in the vapor of a material and blocking up a tube.
One object of the present invention is to provide a CVD apparatus capable of long-term, reliable and efficient production of CVD film with good properties.
Another object of the present invention is to provide a vaporizer for use with a CVD apparatus capable of long-term, reliable and efficient production of CVD film with good quality.
Still another object of the present invention is to provide a semiconductor device comprised of a CVD film having good film quality.
In one aspect of the present invention, the vaporizer for a CVD apparatus is comprised of a material introducing tube, a vaporization chamber and a cooling member. The material introducing tube transports a mixture containing a solution of a CVD film material and a gas carrying the solution. The vaporization chamber is connected to the material introducing tube and vaporizes the material introduced through the material introducing tube. The cooling member cools that portion of the material introducing tube which is adjacent to the vaporization chamber.
Since the cooling member can maintain a low temperature of the portion of the material introducing tube adjacent to the vaporization chamber, a solvent component of the material solution does not vaporize in the material introducing tube and hence the CVD film material does not separate from the material solution in the material introducing tube. This can prevent a variation in the Material""s vaporization characteristics in the vaporization chamber that is attributable to a separated CVD film material (or a vaporization-attributable residue). This allows stable vaporization of the CVD film material and hence stable supply of the vaporized CVD film material to a reaction chamber connected to the vaporization chamber to form CVD film. Consequently, the CVD film can be provided with superior film quality.
Furthermore, since a vaporization-attributable residue is not produced, the residue cannot be delivered from the vaporization chamber as particles of an impurity nor arrive at the reaction chamber. Thus such residue cannot be mixed into a CVD film nor degrade the quality of the CVD film. This allows reliable production of CVD film with good quality. Furthermore, if a CVD apparatus with the vaporizer of the present invention is used to provide a dielectric film for capacitors of memory devices and the like, the dielectric film can have reduced defects, providing an improved product yield of memory devices.
Furthermore, the vaporizer of the present invention for use with a CVD apparatus can also prevent a solution from vaporizing in the material introducing tube, to reduce a variation in the flow rate of a mixture supplied to the vaporization chamber through the material introducing tube that would be introduced when a material solution vaporizes in the material introducing tube. Thus the vaporizer can reduce a variation in the quality of a CVD film that would otherwise be attributed to such variation in the flow rate of the material.
Furthermore, a portion of the material introducing tube adjacent to the vaporization chamber can be maintained at a low temperature and can thus have a temperature prevented from elevating due to the heat from the vaporization chamber. Thus the material introducing tube can be free of a degradation in its material that would otherwise be caused by such temperature elevation. Thus the material introducing tube can be used continuously for a long term.
In one aspect above the vaporizer for a CVD apparatus may include a heat sink formed to transfer heat from a portion thereof adjacent to the vaporization chamber.
In the vaporizer of the present invention for use with a CVD apparatus, a mixture containing a material solution and a gas carrying the solution is supplied to a vaporization chamber through a material introducing tube and the material (the mixture) can thus be delivered through the material introducing tube at a flow rate higher than a liquid material conventionally introduced directly into the vaporization chamber. Thus the temperature elevation of the material introducing tube that is attributed to the heat for vaporizing the material in the vaporization chamber can be smaller than when the liquid material is introduced directly into the vaporization chamber. Accordingly, a relatively simple cooling member, such as a heat sink connected to the material introducing tube, can be used to maintain an adequately low temperature of the material introducing tube. Providing a cooling member simpler in configuration than conventional cooling members can also reduce the cost for manufacturing the vaporizer for use with a CVD apparatus.
Furthermore, the shape of such heat sink can readily be adjusted to readily change the temperature to which the material introducing tube is cooled and thus optimally cool the material introducing tube considering CVD film material types, CVD film forming conditions, and the like.
In one aspect above, in the vaporizer for a CVD apparatus the cooling member may include a coolant path and a coolant supplying member. The coolant path may have a portion adjacent to the vaporization chamber that transfers heat, and the coolant supplying member may introduce a coolant to the coolant path.
As such, if the conditions for vaporizing a material, such as the temperature of the vaporization chamber, are changed variously the amount of the coolant introduced to the coolant path can be adjusted to set any temperature of the portion of the material introducing tube adjacent to the vaporization chamber.
In one aspect above, in the vaporizer for a CVD apparatus the cooling member may include a Peltier element formed to transfer heat from a portion thereof adjacent to the vaporization chamber.
As such, by varying the level of the current supplied to the Peltier element the amount of heat absorbed therein can be varied to readily set any temperature of the portion of the material introducing tube adjacent to the vaporization chamber if the conditions for vaporizing a material are varied. Thus, the temperature of the material introducing tube can be set at a low temperature to prevent vaporization of the material solution and hence more reliably prevent production of a vaporization-attributable residue in the material introducing tube.
In one aspect above, in the vaporizer for a CVD apparatus a heat transferring member may also be provided around the portion of the material introducing tube adjacent to the vaporization chamber and the cooling member may be provided in contact with the heat transferring member.
As such, the cooling member can be provided from the portion of the material introducing tube adjacent to the vaporization chamber with the heat transferring member therebetween, resulting in an enhanced degree of freedom in designing the vaporizer.
In one aspect above, the vaporizer for a CVD apparatus may be comprised of a control member disposed to control the cooling member to change the temperature of the material introducing tube.
As such, the temperature of the material introducing tube can be varied as desired and thus set to a low temperature which prevents vaporization of the material solution. This can more reliably prevent production of a vaporization-attributable residue in the material introducing tube.
Furthermore, since the material introducing tube is not heated above a predetermined temperature, a material forming the tube does not suffer the degradation attributable to the heat of the tube otherwise heated.
In one aspect above, in the vaporizer for a CVD apparatus the CVD film material may contain an organometallic compound and the solution may be obtained by dissolving the material in an organic solvent.
In one aspect above, in the vaporizer for a CVD apparatus the cooling member may cool the material introducing tube to no more than 80xc2x0 C.
In one aspect above, the vaporizer for a CVD apparatus may be comprised of a heating member disposed to heat the interior of the vaporization chamber in a range of 230 to 300xc2x0 C., and a pressure controlling member disposed to provide a controlled pressure of no more than 30 Torr in the vaporization chamber.
As such, the conditions as above in the vaporization chamber are particularly suitable for vaporizing a material for forming a thin film of a high dielectric constant and thus allow long-term, reliable production of such thin film of a dielectric constant with good quality.
In one aspect above, in the vaporizer for a CVD apparatus a covering member may be provided on and thus cover an internal wall surface of the vaporization chamber.
As such, if an accident or the like produces a vaporization-attributable residue that would otherwise adhere to the internal wall surface of the vaporization chamber, the residue adheres to the covering member rather than adheres directly to the internal wall surface of the vaporization chamber. The covering member with the residue adhering thereto can be replaced to readily clean the interior of the vaporization chamber. Thus the maintenance time for the vaporizer can be reduced, resulting in an enhanced operating efficiency of the CVD apparatus, and the CVD apparatus can also be used reliably for a long term.
Furthermore, replacing the covering member to constantly keep clean the interior of the vaporization chamber, allows CVD film to be formed constantly with good quality.
In another aspect of the present invention, the vaporizer for a CVD apparatus is comprised of a vaporization chamber disposed to vaporize a CVD film material, and a covering member provided on and thus covering an internal wall surface of the vaporization chamber.
As such, if using the CVD apparatus for a long term results in producton of a small amount of a vaporization-attributable residue in the vaporization chamber that would otherwise adhere to the internal wall surface of the vaporization chamber, the residue adheres to the member covering the internal wall surface of the vaporization chamber and does not adhere directly to the internal wall surface of the vaporization chamber. The covering member with the residue adhering thereto can be replaced to readily clean the interior of the vaporization chamber. Thus the maintenance of the vaporizer only requires a short period of time and can also be facilitated. The reduction of the time required for the maintenance of the vaporizer for a CVD apparatus can result in an enhanced operating efficiency of a CVD apparatus employing the vaporizer for use with a CVD apparatus.
In one aspect above or another aspect, in the vaporizer for a CVD apparatus the covering member may have an outermost layer containing a polymer film.
The polymer film reacts less with a solid vaporization-attributable residue as a separation of a CVD film material than typical materials constructing the vaporization chamber, such as metal. As such, the polymer film can effectively prevent an internal wall surface of the vaporization chamber from reacting with the CVD film material in the vaporization chamber, to prevent a vapolization-attributable residue from being produced in the vaporization chamber and adhering to the interior of the vaporization chamber. Thus the polymer film can more reliably prevent production of such residue.
In one aspect above or another aspect, in the vaporizer for a CVD apparatus the polymer film may include at least one of polytetrafluoroethylene (PTFE) film or a polyimide film.
In another aspect of the present invention, a CVD apparatus is comprised of a material introducing tube, a vaporization chamber, a reaction chamber and a cooling member. The material introducing tube transports a mixture containing a solution of a CVD film material and a gas carrying the solution. The vaporization chamber is connected to the material introducing tube and vaporizes the material introduced through the material introducing tube. The reaction chamber receives the vaporized, gaseous material. The cooling member cools that portion of the material introducing tube which is adjacent to the vaporization chamber.
Since the cooling member can maintain a low temperature of the material introducing tube, a solvent of the material solution does not vaporize in the material introducing tube adjacent to the vaporization chamber and hence the CVD film material does not separate in the material introducing tube. This can prevent a variation of the material""s vaporization characteristics in the vaporization chamber that is attributable to a separated CVD film material (or a vaporization-attributable residue). This allows stable vaporization of the CVD film material and hence a stable supply of the vaporized CVD film material to a reaction chamber to form CVD film. Consequently, the CVD film can be provided with superior film quality.
Furthermore, since a vaporization-attributable residue is not produced, the residue cannot be delivered from the vaporization chamber as particles of an impurity nor arrive at the reaction chamber. Thus such residue cannot be mixed into a CVD film nor degrade the quality of the CVD film. This allows reliable production of CVD film with good quality. Furthermore, if the CVD apparatus of the present invention is used to provide a dielectric film for capacitors of memory devices and the like, the dielectric film can have reduced defects, providing an improved product yield of memory devices.
Furthermore, the CVD apparatus of the present invention can also prevent a solution from vaporizing in the material introducing tube, to reduce a variation in the flow rate of a mixture supplied to the vaporization chamber through the material introducing tube that would be introduced when a material solution vaporizes in the material introducing tube. Thus the vaporizer can reduce a variation in the quality of a CVD film that would otherwise be attributed to such variation in the flow rate of the material.
Furthermore, a portion of the material introducing tube adjacent to the vaporization chamber can be maintained at a low temperature and can thus have a temperature prevented from elevating due to the heat from the vaporization chamber. Thus the material introducing tube can be free of a degradation in its material that would otherwise be caused by such temperature elevation. Thus the material introducing tube can be used continuously for a long term.
In another aspect above the CVD apparatus may include a heat sink formed to transfer heat from the portion of the material introducing tube which is adjacent to the vaporization chamber.
In the CVD apparatus of the present invention, a mixture containing a material solution and a gas carrying the solution is supplied to a vaporization chamber through a material introducing tube and the material (the mixture) can thus be delivered through the material introducing tube at a flow rate higher than a liquid material conventionally introduced directly into the vaporization chamber. Thus the temperature elevation of the material introducing tube that is attributed to the heat applied in the vaporization chamber to vaporize the material can be smaller than when the liquid material is introduced directly into the vaporization chamber. Accordingly, a relatively simple cooling member, such as a heat sink connected to the material introducing tube, can be used to maintain an adequately low temperature of the material introducing tube. Providing a cooling member simpler in configuration than conventional cooling members can also reduce the cost for manufacturing the CVD apparatus.
Furthermore, the shape of such heat sink can readily be adjusted to readily change the temperature to which the material introducing tube is cooled and thus optimally cool the material introducing tube considering CVD film material types, CVD film forming conditions, and the like.
In another aspect above, in the CVD apparatus the cooling member may include a coolant path and a coolant supplying member. The coolant path may have a portion adjacent to the vaporization chamber transferring heat, and the coolant supplying member may introduce a coolant to the coolant path.
As such, if the conditions for vaporizing a material, such as the temperature of the vaporization chamber, are changed variously the amount of the coolant introduced to the coolant path can be adjusted to set any temperature of the portion of the material introducing tube adjacent to the vaporization chamber.
In another aspect above, in the CVD apparatus the cooling member may include a Peltier element formed to transfer heat from the portion thereof adjacent to the vaporization chamber.
As such, by varying the level of the current supplied to the Peltier element the amount of heat absorbed therein can be varied to readily set any temperature of the portion of the material introducing tube adjacent to the vaporization chamber, if the conditions for vaporizing a material are varied. Thus, the temperature of the material introducing tube can be set at a low temperature to prevent vaporization of the material solution and hence more reliably prevent the production of a vaporization-attributable residue in the material introducing tube.
In another aspect above, in the CVD apparatus a heat transferring member may also be provided around the portion of the material introducing tube adjacent to the vaporization chamber and the cooling member may be provided in contact with the heat transferring member.
As such, the cooling member can be provided from the portion of the material introducing tube adjacent to the vaporization chamber with the heat transferring member therebetween, resulting in an enhanced degree of freedom in designing the CVD apparatus.
In another aspect above, the CVD apparatus may be comprised of a control member disposed to control the cooling member to change the temperature of the material introducing tube.
As such, the temperature of the material introducing tube can be varied as desired and thus set to a low temperature which prevents vaporization of the material solution. This can more reliably prevent production of a vaporization-attributable residue in the material introducing tube.
Furthermore, since the material introducing tube is not heated above a predetermined temperature, a material forming the tube does not suffer the degradation attributable to the heat of the tube otherwise heated.
In another aspect above, in the CVD apparatus the CVD film material may contain an organometallic compound and the solution may be obtained by dissolving the material in an organic solvent.
In another aspect above, in the CVD apparatus the cooling member may cool the material introducing tube to no more than 80xc2x0 C.
In another aspect above, the CVD apparatus may be comprised of a heating member disposed to heat the interior of the vaporization chamber in a range of 230 to 300xc2x0 C., and a pressure controlling member disposed to provide a controlled pressure of no more than 30 Torr within the vaporization chamber.
As such, the conditions as above in the vaporization chamber are particularly suitable for vaporizing a material for forming a thin film of a high dielectric constant and thus allow long-term, reliable production of such thin film of a dielectric constant with good quality.
In another aspect above, in the CVD apparatus a covering member may be provided on and thus cover an internal wall surface of the vaporization chamber.
As such, if an accident or the like produces a vaporization-attributable residue that would otherwise adhere to the internal wall surface of the vaporization chamber, the residue adheres to the covering member rather than adheres directly to the internal wall surface of the vaporization chamber. The covering member with the residue adhering thereto can be replaced to readily clean the interior of the vaporization chamber. Thus the maintenance time for the CVD apparatus can be reduced, resulting in an enhanced operating efficiency of the CVD apparatus, and the CVD apparatus can also be used reliably for a long term.
Furthermore, replacing the covering member to constantly keep clean the interior of the vaporization chamber, allows CVD film to be formed constantly with good quality.
In another aspect above, in the CVD apparatus the covering member may have an outermost layer containing a polymer film.
The polymer film reacts less with a solid vaporization-attributable residue as a separation of a CVD film material than typical materials constructing the vaporization chamber, such as metal. As such, the polymer film can effectively prevent an internal wall surface of the vaporization chamber from reacting with the CVD film material in the vaporization chamber, to prevent a vaporization-attributable residue from being produced in the vaporization chamber and adhering to the interior of the vaporization chamber. Thus the polymer film can more reliably prevent production of such residue.
In another aspect above, in the CVD apparatus the polymer film may include at least one of polytetrafluoroethylene (PTFE) film or a polyimide film.
In another aspect above, the CVD apparatus is used in a semiconductor device manufacturing process.
In still another aspect of the present invention, a semiconductor device is manufactured employing the CVD apparatus in another aspect of the present invention.